Rock drill



Apr. 24, 1923.

C. R. WELCH ROCK DRILL Filed Jan.

fuhr Si .jl EMMNI I NN NY @,R/Velch@ Patented Apr'. 24, 192s.

CLARENCE R. VVELCH;v OF DENVER, COLORADO.

ROCK DRILL.

Application filed January 17, 1920.

T o all whom t may concern.'

Be it known that I, CLARENCE` R. VELCH, a citizen of the United States, residing at the city and county of Denver and State ofy Colorado, have invented certain new and useful Improvements in Rock Drills; and I do declare the following to be a full, clear,

and eXact description of the invention, such panying drawings, andto the characters of reference marked thereon, which form a part of this specification. The object of this invention is to provide simple and eiiicient means in a rock drill for retraoting and releasing the hammer. n

Brieiiy. this comprises a cam member rotatable adjacent the hammer, the cam thereon engaging an offset portion of the hammer and retracting the same against the tension of a heavy spring. When the hammer has been retracted a suiiicient distance, the eX- tension thereon is disengaged from the cam. permitting the spring to forcibly propel the hammer against the drill steel.

In the drawings: Fig. 1 is a longitudinal section through a drill equipped with my invention; and

Fig. 2 is a view indicated by the line 2-2 of Fig. 1, showing the Vhammer construction.

The usual drill casing 10 is provided and thereupon there ismounted, a motor 12, whose drive shaft 14 carries a pinion16 to rotate the chuck 18, which holds the drill steel 20. The shaft 14 also carries a pinion 22,` which meshes with a gear 24,` carried by the cam member 26. This member 26 is provided with a cam face 28,- the releasing end of which terminates in an axially positioned wall 29. On the opposite side of the member 26 a bearing 30 is provided, which travels upon rollers 32, engaging a run 34, formed in the casing; this structure takes Serial No. 352,116.

care of the end thrust on the cam memberv 26. The cam face 28 engages a roller 36,

provided upon an extension 38 of the hammer 40, the body of which is cylindrical and projects through the cam member 26, said cam member being `iournalled on said cylindrical body. The hammer 4() is engaged by a heavy spring 42, which tends to propel it forward and the lower end of the eXtension 38 slides upon and is guided by a rod 44, yxed in the casing.r The forward end of the hammer 40 reciprocates in a cylinder 46 in the ,casing and is disposed for contact with the inner end of the drill steel 20.

In order to supply water tothe steel, a pipe 50 is passed througha passage 52 in the hammer, and into a passage 54 in the` steel 20. This provides a very simple means for supplying water. y

In operation ofthe device, the pinion 22 and gear 24 rotate the cam member 26 so that the roller 36 travels up on the cam face 28, retracting the hammer against the tension of the spring 42, until the roller 36 and extension 38 reachthe end ofthe cam face 28 and fall alongsideJ the wall 29, whereupon the hammer 40` strikes the steel 20.

I claim: Y In a rock drill, a casing, a drill chuck rotatably mounted in one end thereof, a hammer slidably mounted in said casing, a cam member rotatably mounted on a cylindrical portion of said hammer, a lateral extension on said hammer adapted to be engaged by the cam, means cooperating with said extension to prevent rotation thereof, a gear on said cam, means for simultaneously rotating said gear and said chuck, and a spring within the casing and cooperating with said hammer, whereby said hammer will move quickly when released by said cam. d n

In testimony whereof I atliX my signature.

CLARENCE R. WELCH. 

